<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    div {
      width: 100px;
      height: 100px;
      background-color: black;
    }
  </style>
</head>

<body>
  <div onclick="arr()"></div>
  <script>
    function arr() {
      let sre = document.querySelector('div')
      sre.style.width = '1000px'
      sre.style.height = '1000px'

    }
  </script>
</body>

</html>